"Please note that when measuring high-frequency radiation, you will encounter some" strange features ", which can be quite annoying, especially for novices:
In practice, high-frequency radiation rarely weakens continuously with the distance from the emission source: due to reflection, scattering and diffraction (houses, trees, walls, furniture, etc.), a large number of selective concentrations (so-called "hot spots") are often obvious, especially indoors. Here, in the range of only a few centimeters, the intensity of different measurement signals may easily vary from a factor of 10 to 100. Therefore, it is sometimes difficult to find the actual signal source or the maximum intensity of RF radiation.
The high-frequency electromagnetic field can be measured through metal objects, because these objects can be used as antennas, resulting in the "concentration", reflection or forward movement of the corresponding high-frequency radiation. Therefore, power cable is another medium of high-frequency radiation, which may "capture" these electromagnetic radiation and "release" it again in a completely different position. Therefore, even the shielding room may become "polluted" due to irrelevant power cables. In order to avoid this situation, the shielding room must be equipped with a so-called power filter.
Especially using power cables for data transmission (such as Internet, signal, video and audio transmission) is a serious interference and radiation source.
Bottom noise
The so-called bottom noise refers to the bottom limit that makes the actual measurement impossible. Only interference will be detected here. Visually, the Spectran spectrometer will display a collection of small "dots" or strips, which stay at the same place statically or change (noise) every scan. However, depending on the frequency and selected settings, the bottom noise can vary widely and must be determined before starting the measurement.
For this Spectran spectrometer, the bottom noise increases with the decrease of frequency - for example, the bottom noise at 100MHz is significantly higher than that at 5GHz. However, skilled users can often "comb out" useful readings and distinguish between noise and even weak real signals. It is relatively simple to determine the bottom noise: just carry out the following "measurement", without connecting the antenna / or signal source / or connecting a 50 ohm terminal. Any signal may be displayed as the bottom noise of the instrument.
harmonic
When working with a spectrum analyzer, the typical impression is that when processing a strong signal, there will be a certain number of weak signals with fixed offset relative to the actual signal, that is, the so-called "harmonic". The frequency of these "ghost" signals is just on the frequency doubling of the actual signal. For example, a 400MHz signal will also see harmonic signals at frequencies of about 800MHz, 1200MHz and 1600MHZ, a 1800MHz signal will also see signals at frequencies of 3600MHz and 5400mhz, and so on. These signals are usually called second harmonic, third harmonic and so on.
Therefore, when a signal is measured at a frequency point half of the center frequency, it should be considered whether the signal is doubtful. If a relatively strong signal is found there, the previously measured frequency will be a harmonic. In the current firmware, the harmonic of Spectran spectrometer has been attenuated by about 30-50db according to different signal strength.
Wireless LAN and mobile measurement
In order to accurately measure WLAN, WLAN and mobile phone, some particularity needs to be considered, because these two systems are rarely "really active enough" to allow sensitive measurement:
For measuring mobile phones, you need to actively make calls and calls. It is often not enough for the other party to ring. It must also be considered that the mobile phone will significantly reduce the output power when you stop talking!
When measuring WLAN, you should transmit data continuously. If the system only operates in "pin" mode, make sure to use a long sampling time (5S).
Further optimized configuration can be operated in our "LCS" PC software!
Auto falloff mode
This innovative option allows proper automatic insertion or bypass of attenuators. However, for each scan to make the correct decision, the instrument has to perform a short "experimental measurement", which will temporarily delay the scan. The delay length depends on the selected sampling time and is calculated according to the following formula: delay = sampling time / 10. However, the maximum delay is only 10 milliseconds, equivalent to a sampling time of 100 ms. In the automatic attenuator mode, in order to ensure neat operation, the sampling time must be set at least 100ms, otherwise intermittent wrong level readings may occur, especially in the lower frequency range. The delay can be completely avoided by turning off "automatic" mode and manually setting the attenuator.
sensitivity
Note that the bottom noise (corresponding sensitivity) of the spectrum analyzer may vary significantly depending on the frequency. Even a frequency adjustment of only a few MHz may clearly change the bottom noise characteristics. However, in general, the bottom noise of Spectran spectrometer increases with the decrease of frequency, and the sensitivity decreases. A practical example: using the same filter settings, you can measure weaker signals at 5GHz than at 100MHz.
measurement error
Annoni specifies typical accuracy for each model of Spectran spectrometer. However, this means that a higher deviation is also entirely possible. Especially when you approach the so-called bottom noise or the maximum sensitivity of the spectrum analyzer, the accuracy will be reduced in principle.
Even though Spectran spectrometer provides impressive accuracy, considering the price, it should be assumed that there is a higher measurement accuracy than the basic instrument itself in practice. The reason behind this is that there are many factors that can affect the measurement accuracy: they are temperature correlation, repeatability, antenna error, modulation correlation, etc.
According to buwal (see www.buwal. CH), you always expect to expand the measurement inaccuracy by at least 35%, even for absolutely professional equipment. Therefore, the measurement inaccuracy of about + / - 3dB expressed in DB shall be considered in each measurement!
For example, if your measured value is - 45dbm. Then the actual results can be based on the mentioned measurement inaccuracy, which may be in
-42dbm (- 45dbm + 3dB) and - 48dbm (- 45dbm-3db). Therefore, when you want to measure radiation exposure, you should always use the highest value measured, that is - 42dbm. let me put it another way:
When measuring, always add another 3dB as the measurement inaccuracy of your Spectran instrument.
Cursor and zoom functions
Using the wheel knob, a cursor can be activated in spectrum analysis mode. This cursor allows you to display the exact frequency and signal level at a specific point. To activate the cursor, simply turn the dial. The cursor is displayed as a line in the spectrum. You can also press the menu key twice to close the cursor. The spectrum display part under the cursor is drawn in reverse.
Frequency and level at the current cursor position
The spectrum part under the cursor, and the cursor is drawn in reverse
By turning the wheel button, the cursor can be freely positioned on the display screen. The reading displayed in the main display only corresponds to the exposure limit display and demodulation of the current cursor position! The frequency and level display on the current cursor is updated only after a complete scan and is displayed in the first marking area (leftmost). In this mode, the automatic marking function is disabled.
When you press the scroll knob and lock the cursor, you can amplify the signal. Here, the center frequency will be transferred to the frequency at the specified cursor position, the span will be reduced by half, and a new scan will be started. So you can amplify 50% of the signal. You can use this feature to achieve the resolution you need. This is an incredible and very convenient function.
Press the menu button twice to deactivate the function.
Note: the cursor will not be deleted in hold mode!
Tips and tricks
Fast zero span scanning (time domain mode)
Using the so-called "zero span" can achieve almost real-time fast scanning at a fixed frequency. If you find a signal through hotkey 5 (GSM900), just use the cursor to set the correct center frequency. Now set span to "0" and sptime to 1ms. The level on the center frequency is constantly and rapidly updated, including the display in the time domain!
It is very suitable for using the translation approximation mode to locate the signal source and maximum value.
Accelerated scanning in small frequency range
When certain conditions are met, the Spectran spectrometer automatically switches to a special "accelerated" scanning mode. In this mode, the second scan and all further scans will be accelerated by about 300%, and the number of measurement samples up to 1280 will be continuously cached. Therefore, the execution of the "turbo" scan mode depends on the selected RBW filter and span. The maximum available values are as follows:
-3mhzrbw = maximum available span96mhz
- 1mhzrbw = maximum available span32mhz
- 300khzrbw = maximum available span9.6mhz
- 100khzrbw = maximum available span3.2mhz, etc
For example, span96mhz allows you to monitor the full WLAN band.
Large frequency range "turbo" scan
You can use the "full" filter to obtain faster measurements over a wide frequency range. To do this, set the sptime of RBW to "full" to 1ms. The result is extremely high-speed scanning, even in a large frequency range.
However, please note that due to the extremely high filter bandwidth, the current frequency and level readings must be careful! In addition, now, depending on the frequency, the signal level exceeding - 65dbm (at 5GHz) can be detected.
Since this model is also specially designed for less interference processing, it is only recommended to experienced users as a "rapid evaluation tool". Nevertheless, it is still a very convenient function!
Custom measurement settings assignment keys
Keys 0 to 9 can be assigned to the user to customize the configuration (including start / stop frequency, RBW, etc.), and the program number is 100 to 109, corresponding to keys 0 to 9. Simply store these program numbers of the current configuration through the setup & store menu item, and their configuration will be available at any time with the corresponding hotkeys. It's even easier to use our free PC analysis software "LCS". Here, you can even attach text messages. To invoke these factory settings, select "factor" under the "setup" menu.
DECT analysis
Using the "0" key, you can call the DECT analyzer to measure the active DECT mobile phone. By constantly pressing the DECT key (key 0), you can even analyze all 10 channels according to the DECT standard (display: "DECT 0-9"). You will soon be able to see 10 channels currently occupied, even when channel hopping occurs. This channel separation is particularly useful in audio mode. In addition, a very special function is automatic-dect-channel-hopping-mode (DECT auto rotate). Press the DECT key to start the mode automatically. Here, all 10 channels are being measured and displayed one by one. In this way, you will not miss any FM channel. For example, using pkhold can quickly evaluate the strongest detection level of any signal. See 7.11
Calculate the exposure limit of weak signal w / m ² value
Reduce "mrklvl" to "- 90dB" and "- 110dB".
Convert to measurements in other units
As you know, the pkhold function can "freeze" the current reading. Therefore, for the conversion between units, just activate pkhold, and then select a new unit [v / m, MA / m, DBM, DB] in the unit menu μ 5] : the previous data is immediately converted.
Correct settings for manual input and measurement
For this, it is best to use our PC analysis software "MCS". Click here to optimize dozens of "configuration files", including from model
Making to 5GHz WLAN WLAN can be obtained. More information such as channel number, operation provider, etc. can be displayed. Similarly, you can simply "copy" these parameters (for example, a hotkey) using the LCS file manager and transfer them to the Spectran spectrometer.
In general, the following rules apply to most signal types:
1.) if possible, use a small frequency range (span) below 100 MHz to eliminate interference and / or harmonics, so as to achieve fast scanning.
2) "3MHz" RBW and sptime "1ms" settings are usually ideal.
3.) activate minmax mode when processing pulse and modulation signals.
Analyze on your PC
On our website, we provide a free PC analysis software Spectran "MCS" for Spectran spectrometer. This is really multi-purpose professional software, releasing the full potential of Spectran spectrometer. Whenever possible, you should use the software of the Spectran device.
Exposure limits
Exposure limits (personal safety)
For radio transmitters (including mobile phones / cellular communication towers), there are internationally recognized limits and various preventive measures and suggestions. However, the limits specified by different countries, professional organizations or interest groups may vary significantly for various reasons.
The exposure limits in Germany are set by "regulierungsbeh ö RDE f ü R Telekommunikation und post" (Telecommunications and post regulatory authority), which belongs to a branch of "bundesministium f ü R Wirtschaft und Arbeit" (BMWA, Department of Commerce and labor). Most national and international institutions recognize these standards. In Germany, these limits are recorded in "verordnung ü BER Elektromagnetische Felder (26. Blmschv)" (regulations on electromagnetic fields), most of which are
Our other product:
